|I think I agree with most of what you said about the medical ethics issue. For me, some things your post made me think about:|
(1) Are we dealing with a born child or a fetus? From the current legal standpoint, a fetus shouldn't really qualify for any protection from society against idiotic parents. So I think that means i agree with you: once we accept that people can abort babies for any reason (including "I don't feel like being pregnant anymore"), then I don't think there's a legal line to be drawn about aborting babies because you don't like their eye color. Similarly, if people want to have "natural" babies, even one's with down's syndrome, it's hard to say no, given that we think they should be able to abort. Of course, this means we have to accept as legit people who want to give their child pre-natal care via prayer only. I think.
I think it's much harder with already-born babies, especially when you get to cases in which treatments have possible fatal side effects and "not doing anything" involves no chance of death. So you're taking risks to increase quality of life. I don't know how to think about this. Even worse is when you're dealing with an almost certain possibility of death whether you treat or not, but treating involves horrific pain. Would I get my daughter a bone marrow transplant if it gave her a 5% chance to live and otherwise she dies? I probably would. Could I stomach the government requiring that people do that? No.
(2) If we forget the law, and just ask "Given the pro-choice world, what would I counsel my sister to do?" I think the decision largely rests on a cold calculation based on invasivness, probability of disease, and quality of life. I concur with you that in the case of horrific childhood diseases that always result in severe handicap and early death, when the parents know they are carriers, it makes sense to test --- and possibly abort. But that's the easy case. The hard case is when you're just fishing for non-fatal handicaps that don't always severely diminish quality of life, like DS. I don't think you can dismiss the miscarriage rate until you're actually sitting there talking about your own future child. Especially when the miscarriage rate is higher than the probability of having the disease. You're right that technology may wash away this problem soon, but then again, many readers of your blog might be making these decisions later this year.
For me, I would personally find it almost impossible to counsel someone to abort a baby simply because it had down's syndrome. In fact, I think I can safely say that I look down upon people who do so. I wouldn't look down on someone who aborted a baby with Angelman's syndrome or something horrific like that, but I'd have a hard time telling them to do it. But that largely has to do with one's opinions of abortion, pro-choice or not.
And, of course, I think some cases are just beyond the pale, even though they are highly realistic: If someone told me they were aborting a baby because they wanted the other gender, I'd probably have to stop being friends with the person.
(3) What about government action to "force" treatment? To me, this is the most interesting question. We can think of all sorts of things that, if we eliminated them from society, it would just be more efficient. Even dumb things: closest to my heart is left-handedness. If we could just get rid of all the lefties, there'd be a significant economic gain via the synchronization of education and the reduction of highway fatalities. We'll probably be able to eradicate "gay" as well. And from an economic standpoint, there's little reason not to.
Still, it's very scary to me to think about the government makign these decisions. It seems inconsistent to say "you can kill the fetus, but if you choose not to kill the fetus, you have to get it this treatment." On the other hand, we require vaccinations to go to the public schools, so why not.
First, a minor point: I ignored the 1% miscarriage risk of amnio only in the context of a 25% chance of a Batten Disease child. Unless you're specifically worried about something, like Batten Disease, Tay Sachs, or you're high risk for something like Downs, the benefits probably don't outweigh the costs. Now, in the context of Down Syndrome, which I believe is one of the more common positive results from an amnio, I do think one's socioeconomic status legitimately plays a role in one's decision to abort. Certainly it helps to be well-off with a strong network of family to help out, and I can't say I'd look down on someone who was worse off if she chose to abort a DS baby.
As for the vaccinations, a very interesting point, but I think there is a difference. From an epidemiology standpoint, there's very little difference to having only some people vaccinated and having no one vaccinated. In other words, one person's refusal to be vaccinated can have a direct negative consequence on the next guy (especially if the next guy is very young or very old) -- it is a bad idea to have anyone in the population carrying the disease, even if for them it isn't lethal, it might be for someone else.